# iMAC serial port comunication

**URL:** <https://discourse.nodered.org/t/imac-serial-port-comunication/55341>\
**Category:** General\
**Created:** [17 December 2021 12:48 UTC](https://discourse.nodered.org/t/imac-serial-port-comunication/55341 "2021-12-17T12:48:28Z")\
**Posts on this page:** 10\
**Page:** 1

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**Author:** ![stefano.m](https://avatars.discourse-cdn.com/v4/letter/s/b487fb/32.png) [@stefano.m](https://discourse.nodered.org/u/stefano.m)\
**Post date:** [17 December 2021 12:48 UTC](https://discourse.nodered.org/t/imac-serial-port-comunication/55341/1 "2021-12-17T12:48:28Z")

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Hi , I've installed node-red on my iMAC and in my MacBook.  
I normally work with Arduino with the IDE on /dev/cu.usbmodem144201 and /dev/cu/usbseriall-0001 for Esp8266.  
In node-red I can't find these serial ports , I've tried to use the Arduino IDE with node-red , but the result it's the same.  
Should I use a USB to Serial TTL converter ?

Thanks for the attention.  
S.

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**Author:** ![zenofmud](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/zenofmud/32/316_2.png) [@zenofmud](https://discourse.nodered.org/u/zenofmud)\
**Post date:** [17 December 2021 13:04 UTC](https://discourse.nodered.org/t/imac-serial-port-comunication/55341/2 "2021-12-17T13:04:16Z")

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Are you doing something where you can’t use MQTT? That’s how I communicate between esp devices and NR

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<div class="post-metadata">

**Author:** ![stefano.m](https://avatars.discourse-cdn.com/v4/letter/s/b487fb/32.png) [@stefano.m](https://discourse.nodered.org/u/stefano.m)\
**Post date:** [17 December 2021 13:15 UTC](https://discourse.nodered.org/t/imac-serial-port-comunication/55341/3 "2021-12-17T13:15:45Z")

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No , I am looking to read the pin value. Simple...  
I've installed serialport,and Arduino Palette ... but nothing.

Thanks

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**Author:** ![TotallyInformation](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/totallyinformation/32/31_2.png) [@TotallyInformation](https://discourse.nodered.org/u/TotallyInformation)\
**Post date:** [17 December 2021 13:26 UTC](https://discourse.nodered.org/t/imac-serial-port-comunication/55341/4 "2021-12-17T13:26:23Z")

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I believe the command `ls /dev/{tty,cu}.*` will list all of the serial ports on the Mac (my Macbook Pro isn't on right now so I can't test).

There doesn't appear to be a way to access the device via a fixed ID as there is on Linux with devices in `/dev/serial/by-id/`.

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<div class="post-metadata">

**Author:** ![stefano.m](https://avatars.discourse-cdn.com/v4/letter/s/b487fb/32.png) [@stefano.m](https://discourse.nodered.org/u/stefano.m)\
**Post date:** [17 December 2021 13:32 UTC](https://discourse.nodered.org/t/imac-serial-port-comunication/55341/5 "2021-12-17T13:32:40Z")

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Thanks, in the Arduino IDE I've read the port to comunicate with the board , and in node-read I want to use the same ...  
I use the command ls /dev/{tty,cu}.\* and give me the port that I use in Arduino IDE , and it is correct.  
I don't understand why node-red don't see these...

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**Author:** ![TotallyInformation](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/totallyinformation/32/31_2.png) [@TotallyInformation](https://discourse.nodered.org/u/TotallyInformation)\
**Post date:** [17 December 2021 13:34 UTC](https://discourse.nodered.org/t/imac-serial-port-comunication/55341/6 "2021-12-17T13:34:36Z")

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Remember that using the tty entry is blocking. So if it is open in the IDE, you can't open it in Node-RED or visa versa. At least that is my understanding. Not sure if you can use the `cu` entry, that seems to be for sending, not sure if it also recieves as I've not really used serial on a Mac.

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<div class="post-metadata">

**Author:** ![stefano.m](https://avatars.discourse-cdn.com/v4/letter/s/b487fb/32.png) [@stefano.m](https://discourse.nodered.org/u/stefano.m)\
**Post date:** [17 December 2021 13:37 UTC](https://discourse.nodered.org/t/imac-serial-port-comunication/55341/7 "2021-12-17T13:37:33Z")

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Thanks. Yes I tried to close Arduino IDE and the result is the same ...  
Thanks again

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<div class="post-metadata">

**Author:** ![TotallyInformation](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/totallyinformation/32/31_2.png) [@TotallyInformation](https://discourse.nodered.org/u/TotallyInformation)\
**Post date:** [17 December 2021 14:02 UTC](https://discourse.nodered.org/t/imac-serial-port-comunication/55341/8 "2021-12-17T14:02:45Z")

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Remember that NR will open the serial port at startup so if the IDE already had it locked, you would have to close it and then restart NR.

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<div class="post-metadata">

**Author:** ![stefano.m](https://avatars.discourse-cdn.com/v4/letter/s/b487fb/32.png) [@stefano.m](https://discourse.nodered.org/u/stefano.m)\
**Post date:** [17 December 2021 14:04 UTC](https://discourse.nodered.org/t/imac-serial-port-comunication/55341/9 "2021-12-17T14:04:29Z")

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Ok,I will try.  
Thank you

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<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/1X/d073cd938eafa2e558d7c2cd59003b3ef4963033.png) [@system](https://discourse.nodered.org/u/system)\
**Post date:** [15 February 2022 14:05 UTC](https://discourse.nodered.org/t/imac-serial-port-comunication/55341/10 "2022-02-15T14:05:11Z")

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